This example visualizes global population distribution by rendering a world map with cities represented as scaled circles. The map displays land masses, graticules, and country borders, while city markers use a square-root scale to encode population size. The visualization is built with React and D3 v5, using `geoNaturalEarth1` projection via `d3.geoPath` and topojson data from the world-atlas package. Population data comes from a CSV of world cities, with React hooks managing asynchronous data loading.